Heat exchanger

ABSTRACT

A heat exchanger for cooling a liquid. The heat exchanger includes a cylindrical outer shell which has a cooling coil in thermal conductive contact with the outer surface of the outer shell. A cylindrical inner shell is mounted within the outer shell with the outer surface of the inner shell being a short distance to the inner surface of the outer shell. A plug is positioned in one end of the outer shell and said plug is spaced from the adjacent end of the inner shell to allow liquid to flow between the end of the inner shell and the plug. An inlet is connected to the other end of the outer shell to allow liquid to flow between the inner and outer shells toward the space between the one end of the inner shell and the plug. An outlet is connected to the other end of the inner shell to carry away liquid from the interior of the inner shell, which liquid has been cooled during its flow between the inner and outer shells.

United States Patent inventor Alfred K. Burkell Westchester, lll. Appl.No. 841,244 Filed July 14, 1969 Patented Jan. 26, 1971 AssigneeGraymillsCorporation Chicago, Ill. a corporation of Illinois HEATEXCHANGER 11 Claims, 3 Drawing Figs.

US. Cl 165/71, 165/163: 62/394 Int. Cl Fl6f l/34 Field of Search 165/71-References Cited UNITED STATES PATENT 2,356,530 8/1944 Pflock 2,801,8318/1957 Clarkson Primary Examiner-Martin P. Schwadron AssistantExaminer-Theophil W. Streule Attorney-Stone, Zummer, Livingston & Aubel165/154X .i ss sex ABSTRACT: A heat exchanger for cooling a liquid. Theheat exchanger includes a cylindrical outer shell which has a coolingcoil in thermal conductive contact with the outer surface of the outershell. A cylindrical inner shell is mounted within the outer shell withthe outer surface of the inner shell being a short distance to the innersurface of the outer shell. A plug is positioned in one end of the outershell and said plug is spaced from the adjacent end of the inner shellto allow liquid to flow between the end of the inner shell and the plug.An inlet is connected to the other end of the outer shell to allowliquid to flow between the inner and outer shells toward the spacebetween the one end of the inner shell and the plug. An outlet isconnected to the other end of the inner shell to carry away HEATExcuANcER BACKGROUND OF THE INVENTION In the printing art and especiallyin lithography, an alcohol water mixture is applied to certain printingrolls. As is well known, this alcohol-water mixture was originally heldin foun tains through which certain rolls rotated to pick up thealcohol-water mixture. With the advancement of the lithographic art, itwas found that it is desirable to circulate the alcohol-water mixturethrough the fountains in order to have a uniformity of liquid in each ofthe fountains. Also, it has been found that it is desirable to maintainthe temperature of the alcohol-water mixture at a prescribed temperatureto have a uniformity of printing during a given runv It may beappreciated that as the press is operated, heat is generated, and thetemperature of the alcohol-water rises as the press heats up, so thatthe quality of the printing changes during the course of the run. Itfollows that in order to maintain a given standard of quality and tomaintain a given balance of colors from various printing inks, it isnecessary to keep uniform the temperature of the liquid applied to therolls.

Another problem is encountered in lithographic printing is that as thetemperature of the alcohol-water mixture rises, an algae in thealcohol-water mixture tends to increase its growth. This algae resultsin particles being picked up on rolls and results in imperfections beingprinted on the work.

In order to maintain a constant temperature of the alcoholwater mixturein the printing press, a heat exchanger is utilized to cool the liquidto a desired temperature, such as 70 F. The heat exchangers which havebeen used heretofore present a problem in that the algae which grows,irrespective of care and cooling, tends to build up in the heatexchanger and render the heat exchanger inetficient.

SUMMARY OF THE INVENTION The present invention relates to a heatexchanger for use in connection with a printing press which isparticularly adapted for cooling an alcohol-water mixture. The heatexchanger has a high rate of flow adjacent to its cooling surface sothat the liquid does not allow any algae to build up on the coolingsurface, and thereby impede the efficiency of the cooling of the liquidby forming a thermal barrier between the cooling surface and the liquid.The construction of the heat exchanger is such that it provides a largecooling surface to provide an efficient cooling of the liquid, and atthe same time, provides a compact heat exchanger which does not occupy alarge amount of space. The construction of the present heat exchangerprovides a high rate of flow past the cooling surface with a pump whichis relatively small in capacity.

The construction of the present heat exchanger allows ready disassemblyof the heat exchanger for cleaning, which cleaning may be done with aminimum of effort and without special tools. The heat exchanger includesa cylindrical outer shell which has a cooling coil in thermal contactwith the outer shell to define a thin cylindrical space between theinner shell and the outer shell. A plug is positioned in sealing contactwith the outer shell, but space is provided between the end of the innershell and the plug to allow a liquid entering the space between theinner shell and the outer shell to flow between the two shells to theend of the inner shell adjacent to the plug and then flow up into theinside of the inner shell. An outlet is in communication with theinterior of the inner shell to carry away the cooled liquid. The innershell may be readily removed from within the outer shell so that theinterior and exterior of the inner shell and the interior of the outershell may be quickly and efficiently cleaned with a minimum of ef-' forton the part of a maintenance person.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a side elevation of across-sectional view through a case in which two heat heat exchangersembodying the herein disclosed invention are mounted and shown connectedto a conventional refrigeration compressor unit;

FIG. 2 is a cross-sectional view taken on line 2-2 of FIG. I showing theinterior construction of one of the heat exchangers of FIG. I; and

FIG. 3 is a cross-sectional view taken on line 33 of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawingsand especially to FIG. 1, a liquid cooling system is shown therein andis generally indicated by numeral 10. The system generally includes acase 12 which has mounted therein a pair of identical heat exchangers l4and I6, which heat exchangers are conventionally connected to aconventional refrigeration compressor unit 18.

The case 12 is conventional in its construction in that it includes afloor 22 having four side walls 24 connected thereto and an aperturedtop 26 connected to the side walls. The heat exchangers l4 and I6 arepositioned in the case 12 and are aligned with each of a pair ofapertures in the top 26. The remaining space in the case filled with athermal insulating material 28.

Referring now to FIGS. 2 and 3, a specific construction of the heatexchanger 14 is shown therein. The construction of heat exchanger 16 isidentical to the construction of heat exchanger 14. Therefore, theconstruction of heat exchanger 14 only will be described in detailhereinafter. The heat exchanger 14 generally consists of a thin-wall,cylindrical, thermal-conductive, metallic outer shell 30, a coppercooling coil 32 helically wound around and in thermal contact with theouter surface of outer shell 30, a top plug 34 sealingly connected tothe top of the outer shell 30, a thin-wall, cylindrical,thermal-conductive, metallic inner shell 36 mounted on and supported bythe top plug, and a bottom plug 38 mounted in the bottom of the outershell 30. A connecter 40 holds the top plug 34 in sealing engagementwith the adjacent end of the outer shell 30. An inlet pipe 42 isconnected to the outer shell, and a drain pipe 44 is connected to theinterior of the inner shell.

The outer shell 30 is a right circular cylinder and has an inletaperture 45 communicating with the inlet pipe near its upper end. A sealflange 46 is formed integral with the top end of the outer shell 30 andextends outwardly from the side of the outer shell. Adjacent to thesealed flange 46 is inlet aperture 45, formed in a side of the outershell. The inlet pipe 42 is fixed to the outer shell in registry withthe inlet aperture to allow a liquid to flow into the interior of theouter shell. The seal flange has a gasket 48 mounted insealingengagement therewith to provide a conventional sealing means between theouter shell and the top plug.

The top plug 34 includes a generally cylindrical body 50 which has a topplug seal flange 52 formed integral therewith. The flange 52 sealinglyengages the gasket 48. The body has an annular inlet groove 54 formedtherein, which inlet groove communicates with the inlet pipe 42 so thata liquid may be distributed about the end of the outer shell. An outletport 56 is formed in body 50, and an outer fitting 58 is threadedlymounted in the outlet port 56. The fitting 58 is connected to a pipe 60which returns the liquid to a liquid circulatory system. The plug 50includes an annular recess 62 in which is fixedly and sealingly mountedone end of the inner shell 36. The plug 34 has a connector aperture 64extending axially through the center of the body 50 to receive a portionof the connector 40.

The bottom plug 38 includes a cylindrical body 66. The plug body 66 hasformed therein a drain port 68 which is connected to the drain pipe 44.The drain pipe is connected to an outlet valve which is not shownherein. The body 66 also has an axial threaded aperture 70 which isaligned with connector aperture 64 and also receives the connector 40.Sealingly connected to the plug 38 at an annular recess 71 is the outershell.

Mounted below the bottom plug 38 and in engagement therewith is a woodenbottom plate 72, which plate contains a pair of axial apertures 74 andcommunicating screw recesses 76. The bottom plate rests on floor 22 ofthe case.

The connector 40 includes a head 78 which has a handle 80 fixed therein.A washer 82 is mounted in engagement with the head 78 and with the topplug 34 to provide a seal around aperture 64. A rod 84 is fixed to head78 and extends through the washer 82, through the aperture 64, andscrews into threaded aperture 70. The end of rod 84 is externallythreaded. A pair of screws 86 are positioned in their respective axialapertures 74 and screws recesses 76 and secure the body 66 to the bottomplate 72. I

The cooling oil 32 is helically wound around the outer surface of theouter shell 30 and is in thermal contact with the outer surface of theouter shell. A thennal mastic 88 holds the cooling coil in position. Thecooling coil is connected to a refrigerant pipe 90, which in turn isconnected to expansion valve 92, which expansion valve is conventionallyconnected to the conventional refrigeration unit 13.

As is conventional, the refrigeration unit provides a compressedrefrigerant to the expansion valve 92, and the expansion of therefrigerant causes the refrigerant to cool. The cold refrigerant iscirculated through the cooling coil 32, thereby cooling the coolingcoil. The cooling of the cooling coil also cools the outer shell.

When the present heat exchanger is connected to a conventional printingpress, a pump, which is not shown, delivers an alcohol-water mixture tothe inlet pipe 42. The alcohol-water mixture flows through the inletaperture 45 and into the inlet groove 54. The alcohol-water mixture thencirculates around the top plug 34 in the inlet groove 54, and thealcohol-water mixture then flows downward between the outer surface ofthe inner shell 36 and the inner surface of the outer shell 30. In aspecific construction, it is found that a space of approximatelyone-sixteenth of an inch is desirable for the distance between the innersurface of the outer shell and the outer surface of the inner shell sothat there is a thin layer of flow of liquid adjacent to the coolingsurface of the outer shell. The liquid flows downward toward the bottomplug 38. It should be noted that there is a high rate of flow adjacentto a large cooling surface so that there is an efficient cooling of theliquid. The high rate of flow serves to prevent any buildup of algaewhich may tend to occur on the cooling surface of the outer shell, whichalgae could act as an insulator between the liquid and the coolingsurface. The liquid flows downward until it reaches the bottom portionof the inner shell 36 and then flows between the end of the inner shell36 and the plug 38. The liquid then reverses direction and flows upwardinside the inner shell 36 and to the outlet port 56. The liquid thenflow through fitting 5$ into pipe 60, from whence it s carried to thecirculating system.

The present heat exchanger provides an efficient cooling system for thealcohol-water mixture. A further advantage to the system is that theheat exchanger may be conveniently and readily cleaned. in order toclean the heat exchanger 14, it is necessary only to interrupt the flowof liquid to the heat exchanger and then drain the liquid within theheat exchanger through the drain port 68 into drain pipe 44. Once theliquid is drained, the handle 80 is rotated to disengage the rod 84 fromthe plug 33. The plug 34 is then lifted, which also lifts out theconnector 40 and the inner shell 36. With the inner shell and the upperplug removed, it may be appreciated that the outer shell may be quicklyand conventionally wiped out to remove any algae may have built upwithin the heat exchanger. Also, the interior and exterior of the innershell may be quickly and conveniently wiped out to remove any algae. Inorder to reassemble the heat exchanger, it is necessary only to drop thetop plug 34 back into position so that the flange 52 sealingly engagesthe gasket 48. The threaded end of rod 84 is placed into engagement withthreaded aperture 70, and the handle is rotated until the rod is drawnup tight against the top plug, thereby creating a seal between the plugand the gasket 48. The heat exchanger is ready for use after the drainpipe is closed.

From the foregoing description, it is readily apparent that the instantheat exchanger provides an efficient means for cooling an alcohol-watermixture in a thin layer of flow, so that the alcohol-water mixture iscooled efficiently but the rate of flow of mixture is great along thecooling surface so that there is little or no opportunity for algae toform on the cooling surface, which algae would act as an insulator andthereby reduce the efiiciency of cooling. The sidewalls of the heatexchanger, and in particular the cooling coil, are surrounded by athermal insulator so that the cooling coil is thermally insulated fromthe side walls of the case 12. Thereby, there is a minimum loss ofcooling effect to the side walls of the case. This renders the overalloperation of the unit to be efficient, and there is no appreciablecooling of the side walls so that moisture does not condense on theoutside walls of the case.

Although specific terms such as downward, upward," top, and bottom havebeen used in the description of the preferred embodiment, it is readilyapparent that those skilled in the art may orient the positions of thevarious parts in a different manner. The use of these terms is solelyfor purposes of illustration, in compliance with the requirements of thePatent Act of 1952, and these terms and the specific description of thepresent invention are in no way intended to limit the scope of thepresent invention.

1 claim:

1. A heat exchanger for cooling a liquid used in printing comprising, incombination, a metallic heat-conductive thinwalled cylindrical outershell, a helical cooling coil mounted in thermal contact with the outersurface of the outer shell, a top lug removably sealingly mounted in oneend of said outer shell, said top plug having a circumferential inletgroove and an outlet port extending therethrough, a bottom plugsealingly engageable with the other end of the outer shell, acylindrical inner shell having one end sealingly fixed to the top plug,said inner shell having its outer surface a short distance from theinner surface of the outer shell, said inner shell having its other endadjacent to but spaced from the bottom plug to allow a liquid to flowbetween the other end of the inner shell and the bottom plug, wherebyliquid delivered to the inlet groove flows between the outer and innershells to the space between the end of the inner shell and the bottomplug and the direction of flow of liquid is reversed to flow out of theoutlet port in the top plug.

2. A heat exchanger for cooling a liquid as defined in claim 1 whereinthe distance between the outer surface of the inner shell and the innersurface of the outer shell is approximately one-sixteenth of an inch.

3. A heat exchanger for cooling a liquid as defined in claim 1 whereinthe bottom plug includes an outlet port for draining liquid from theouter shell.

4. A heat exchanger as defined in claim 1 including a rod extendingthrough the top plug and being connected to the bottom plug for holdingthe top plug in position and sealingly connected to the outer shell.

5. A heat exchanger as defined in claim 1 wherein the bottom plug hasformed therein an outlet port for draining liquid from the outer shell,and including a rod extending through the top plug and being connectedto the bottom plug for holding the top plug in position and in sealingengagement with the outer shell.

6. A heat exchanger for affecting the temperature of a liquidcomprising, in combination: an outer shell; means for conducting heatconnected to the outer surface of the outer shell; an inner shellmounted within the outer shell and the outer surface of the inner shellbeing spaced a short distance from the inner surface of the outer shell;an inlet for providing liquid to the heat exchanger positioned adjacentto one end of the outer shell; an outlet positioned adjacent to the sameend of the outer shell, whereby liquid flowing from the inlet flowsbetween the inner and outer shells to the end of the inner shell andthen reverses flow to flow out from the interior of the inner shellthrough the outlet.

7. A heat exchanger as defined in claim 6 including a top plug sealinglyconnected to the outer shell and having the inner shell supported on thetop plug.

10. A heat exchanger as defined claim 7 wherein the top plug includes anannular inlet groove communicating with the inlet to distribute liquidabout the one end of the outer shell.

11. A heat exchanger as defined in claim 6 wherein the means forconducting heat is a helical copper coil mounted on and in thermalcontact with the outer surface of the outer shell.

22 33 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent3-557-868 Dated Januarv 26. 1971 Invent0r( Alfred K. Burkell It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

Col. 1, line 22, insert whichafter "problem";

line 56, after "shell" first occurrence, insert An inner shell ispositioned within the outer shell-.

Col. 4, line 29, "lug" should be -plug-.

Signed and sealed this 20th day of April 1971.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. WILLIAM E. SCHUYLER, JR. Attestlng- OfficerCommissioner of Patents

1. A heat exchanger for cooling a liquid used in printing comprising, incombination, a metallic heat-conductive thinwalled cylindrical outershell, a helical cooling coil mounted in thermal contact with the outersurface of the outer shell, a top lug removably sealingly mounted in oneend of said outer shell, said top plug having a circumferential inletgroove and an outlet port extending therethrough, a bottom plugsealingly engageable with the other end of the outer shell, acylindrical inner shell having one end sealingly fixed to the top plug,said inner shell having iTs outer surface a short distance from theinner surface of the outer shell, said inner shell having its other endadjacent to but spaced from the bottom plug to allow a liquid to flowbetween the other end of the inner shell and the bottom plug, wherebyliquid delivered to the inlet groove flows between the outer and innershells to the space between the end of the inner shell and the bottomplug and the direction of flow of liquid is reversed to flow out of theoutlet port in the top plug.
 2. A heat exchanger for cooling a liquid asdefined in claim 1 wherein the distance between the outer surface of theinner shell and the inner surface of the outer shell is approximatelyone-sixteenth of an inch.
 3. A heat exchanger for cooling a liquid asdefined in claim 1 wherein the bottom plug includes an outlet port fordraining liquid from the outer shell.
 4. A heat exchanger as defined inclaim 1 including a rod extending through the top plug and beingconnected to the bottom plug for holding the top plug in position andsealingly connected to the outer shell.
 5. A heat exchanger as definedin claim 1 wherein the bottom plug has formed therein an outlet port fordraining liquid from the outer shell, and including a rod extendingthrough the top plug and being connected to the bottom plug for holdingthe top plug in position and in sealing engagement with the outer shell.6. A heat exchanger for affecting the temperature of a liquidcomprising, in combination: an outer shell; means for conducting heatconnected to the outer surface of the outer shell; an inner shellmounted within the outer shell and the outer surface of the inner shellbeing spaced a short distance from the inner surface of the outer shell;an inlet for providing liquid to the heat exchanger positioned adjacentto one end of the outer shell; an outlet positioned adjacent to the sameend of the outer shell, whereby liquid flowing from the inlet flowsbetween the inner and outer shells to the end of the inner shell andthen reverses flow to flow out from the interior of the inner shellthrough the outlet.
 7. A heat exchanger as defined in claim 6 includinga top plug sealingly connected to the outer shell and having the innershell supported on the top plug.
 8. A heat exchanger as defined in claim7 including a bottom plug sealingly connected to the other end of theouter shell and being spaced from the adjacent end of the inner shell toallow liquid to flow between the adjacent end of the inner shell and thebottom plug.
 9. A heat exchanger as defined in claim 8 including a rodextending through the top plug and being connected to the bottom plugfor holding the top plug in position and sealingly connected to theouter shell.
 10. A heat exchanger as defined claim 7 wherein the topplug includes an annular inlet groove communicating with the inlet todistribute liquid about the one end of the outer shell.
 11. A heatexchanger as defined in claim 6 wherein the means for conducting heat isa helical copper coil mounted on and in thermal contact with the outersurface of the outer shell.